In this study, a novel generator for the single-effect LiBr-H 2 O absorption chiller using solar energy was investigated. A dual-chamber vortex generator (DCVG) consisted of a lower chamber and an upperchamber. The hot weak LiBr-H 2 O liquid entered the lower chamber tangentially through a small nozzle to create a strong vortex flow. Due to the rotating flow, the pressure was reduced toward the central portion of the lower chamber. Experiments were conducted under different solution flow rates and temperatures. The experimental results showed that the lower pressure developed in the lower chamber could reduce the saturated temperature and help the evaporation in the generator that is more heat could be utilized to generate more refrigerant vapor. When the inlet temperature was 90℃, the COP of a solar absorption chiller using the DCVG could reach 0.83, which was higher than of the conventional absorption chiller by 22%.
dual-chamber vortex generator, absorption chiller, solarIn recent years, many researches have been carried out on refrigeration systems driven by solar energy, which achieves conservation of conventional energy and reduction of environmental pollution. In order to improve coefficient of performance (COP) and reduce the heat source temperature, many kinds of novel solar absorption refrigerant systems were developed and studied [1][2][3][4][5][6][7] . Because of the difficulties associated with the solar-heating system's long-term operation at a steady state, a refrigeration cycle powered by both heat and electric energy was proposed. A compressor was used to maintain stable energy input to the absorption refrigeration system, though this still consumed electric energy [1] . A pump-free absorption refrigeration system without solution pump was attractive [4] since this system was driven by a low-temperature heat source. A second generator together with an efficient lunate thermosiphon elevation tube was used to reduce the minimum driving temperature of system and improve the solar energy utilization. Spiral grooved tube was used to enhance the heat and mass transfer of the falling film generator [7] . The heat and mass transfer were enhanced through spraying solution into the spiral grooved tubes directly which were distributed in the falling film generator. The utilization of low-temperature heat source for absorption chiller was improved.In this paper a novel dual-chamber vortex generator was proposed for the solar absorption chiller. A dual chamber vortex generator (DCVG) consisted of a lower chamber and an upper chamber. Due to the rotating flow, the pressure and the saturated temperature of solution were reduced in the vortex generator. The available temperature difference of lower-temperature heat source from an external resource increased to generate more refrigerant vapor and improve the COP of the solar absorption chiller.